Familiarize yourself with the radio options available for IoT projects like LoRA, SigFox, ZigBee, Wi-Fi, and Bluetooth to see which is best for your use case.
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The Internet of Things is a collection (or “stack”) of different components that connect software, systems, and people via internet technology. One of these crucial components is the communication network, enabled by IoT wireless technology, the communication network is the gateway between an IoT device (a “thing”) and a software platform ( Bridgera IoT for example).
IoT Wireless Technology in its simplest form requires a radio capability that can receive and broadcast radio waves as a means for transmitting signals or data. Below and in the above Slide Share is an overview on radio frequencies and how they support IoT wireless technology solutions.
A radio wave is an electromagnetic frequency used for long distance communication. IoT solutions rely on IoT wireless technology, leveraging radio waves that follow a specific protocol based on the design intent of the IoT system. Radio protocols are used by IoT devices to transport data to cloud platforms where a physical or wired connection does not exist. There are many different protocols to choose with characteristics varying in areas of power consumption, physical size, travel distance, data size, and transport technology availability.
There’s a good chance that you haven’t thought about radio waves since your last science fair project, so let’s go over the basics before we dive further.
A radio wave is an electromagnetic wave that travels at the speed of light. The wavelength of an electromagnetic signal is inversely proportional to the frequency.
Amplitude indicates the strength of the RF signal. This varies depending on whether a 1 or 0 is present in the digital signal. This modulation is not ideal due to the amount of noise in the transmission medium. Frequency-Shift Keying (“FSK”) makes slight changes to the frequency of the carrier signal to represent data in a manner that’s suitable for propagation through the air at low-to-moderate data rates. FSK also avoids the impacts of common noise.
Another type of modulation is Phase-Shift Keying (“PSK”). PSK causes changes in the signal’s phase, while the frequency remains constant. Like FSK, PSK is mostly immune to common noise that is based in shifts in amplitude.
Frequency is the number of times per second the signal repeats itself, and is measured in hertz (“Hz”). Phase represents how far the signal is offset from the reference point.
Radio frequency bands are, quite simply, any of the electromagnetic wave frequencies that are used in radio communication. They range from 3khz to 300Ghz and encompass everything from amateur radio bands to mobile phones and beyond. There are multiple types of bands as well:
Radio frequencies are versatile, but like any job, it’s up to you to choose the right tool that suits your IoT wireless technology needs. Does your device frequently transfer massive amounts of data? You’ll want a high-bandwidth solution. Does your device need to transmit data over a long distance? A lower frequency will do the job. There are many factors to consider when choosing a radio solution, but there are also many choices available for whatever your needs may be.
For long range connectivity, many IoT wireless technology solutions will leverage cellular networks, since they typically have readily-available development hardware and well-defined protocols. Cellular technologies like 3G and 4G (and soon, 5G) are widely used in IoT systems. 2G was also used, but has largely been retired since AT&T shut down the 2G service in 2016.
However, cellular networks are not without disadvantages. They are expensive, first and foremost. They’re also designed for voice and low-latency communications, which are not typical requirements of most IoT wireless technology solutions. Finally, the cellular device certification processes are time-consuming and expensive, which can be prohibitive for some smaller IoT solutions.
New LPWA networks are entering the IoT space to address some of the unique needs of IoT devices. For example, LPWA networks extend coverage into difficult radio environments. They also support very low power operation, thus enabling long battery life. Two of these emerging solutions are Licensed Spectrum LPWAs and Unlicensed Spectrum LPWAs.
LoRa (short for Long Range) continues to gain attention in the marketplace. It offers a compelling mix of long range, low power consumption, deep indoor coverage, and secure data transmission. LoRa operates in the unlicensed <1GHz frequency range. It uses spread spectrum technology so that adjacent transmitters are less likely to interfere with each other. This increases the capacity of each gateway. Spread spectrum communications also provide a “coding gain” over narrow band communications. This results in a stronger communications link, which can support longer range communications. LoRa data rates range from 0.3 kbps to 50 kbps and can support a range of up to 15km.
While the range of the LoRa system is attractive, there are trade offs. To achieve the longest range, you must use very low data rates. For example, a 15km range uses a data rate of around 100-300 bps and the range drops quickly as data rates increase. The lower the data rate, the longer it takes to transmit data which, in turn, drains battery power. A solid LoRa design balances data volume and transmission speed with power consumption and range requirements. This IoT wireless technology system is best for applications that send only a few bytes of data, a few times per day. It is not ideal for wireless systems that send large amounts of data, require guaranteed quality of service (QoS), or require low latency or tight synchronization.
Sigfox uses low data rate transmission and sophisticated signal processing to effectively avoid network interference, and ensures the integrity of the transmitted data. This IoT wireless technology solution allows bidirectional communication, but always initiated by the device. As such, Sigfox is effective for communications from endpoints to base stations (uploads). However, it is not effective for communications from base stations to endpoints (downloads). Sigfox consumes a fraction (1%) of the power used through cellular communication. This network solution would be ideal for one-way systems including basic alarm systems, simple metering, and agricultural and environmental sensors.
Ingenu is another proprietary LPWA solution. This IoT wireless technology originally focused on smart meter and oil and gas applications. It has since expanded into other IoT wireless applications including urban and agricultural environments.
The Ingenu solution uses Random Phase Multiple Access (RPMA) technology. RPMA enables data rates in the hundreds of thousands of bits per second (50x other LPWA solutions). The system utilizes the 2.4 GHz unlicensed and universal frequency band. This offers larger bandwidth, greater flexibility, and reduces the chance of interference. Ingenu also uses channel coding (Viterbi algorithm) to guarantee data delivery and provide high quality of service (QoS). It is tightly synchronized to support low latency applications and uses 256-bit encryption and two-way authentication to provide enterprise level security.
These great features offered by Ingenu enable higher data throughput rates than Sigfox and LoRa. However, when combined, these benefits consume significantly more power than their IoT wireless technology counterparts. Operating in the 2.4 GHz band, Ingenu encounters more data loss from obstructions, like water or packed earth. Fortunately, RPMA technology exists to counter this issue. RPMA, or Random Phase Multiple Access, is one of the more complex IoT wireless technologies. It utilizes antenna diversity and requires much more processing power than other solutions. While this does enable applications not possible with LoRa or Sigfox, it also increases system complexity, power consumption, and hardware expenses.
Using RPMA, Ingenu claims to require fewer access points than cellular, LoRa, and Sigfox, while providing the same coverage area. The protocol also enables precise location tracking, which Sigfox and LoRa do not. Like LoRa, Ingenu is capable of effective bidirectional transmission. Overall, in weighing the pros and cons, Ingenu may be one of the best IoT wireless technology solution options.
All LPWA networks require some terrestrial infrastructure for IoT device communication. In some cases, such as maritime applications or extremely remote areas, there may be no available gateways (cell towers for example) and therefore satellite is one of the few viable IoT wireless technology options available. Unlike the IoT wireless technology solutions we have discussed up to this point, satellite solutions can be very expensive. The higher cost is due to a low volume market and the expense involved in satellite deployment. Satellite enabled devices require higher power and may also require a sizable antenna.
We define medium range as a radio solution with signal range no greater than 100 meters. Some of these technologies may use a star or mesh node architecture to acquire greater range. Nevertheless, no single link will span more than 100 meters. These technologies are sometimes referred to as “Local RF.” The most common medium range IoT wireless technologies include ZigBee, Wi-Fi, z-Wave, and Thread.
Designed on top of the IEEE 802.15.4 standard, ZigBee is a self-healing, secure, robust, and mesh-capable protocol. It can scale to thousands of nodes across large areas. ZigBee has been around for ~10 years and has ~1 billion devices deployed globally. The specification continues to evolve.
Within a ZigBee system architecture, there are 3 device types. The ZigBee Coordinator (ZC), ZigBee Router (ZR), and ZigBee End Device (ZED). There is only one Coordinator in the network.
